U.S. patent application number 17/726709 was filed with the patent office on 2022-08-11 for osteotomy plate, plate driver and method for their use.
This patent application is currently assigned to OrthoHelix Surgical Designs, Inc.. The applicant listed for this patent is OrthoHelix Surgical Designs, Inc.. Invention is credited to Jackson R. HEAVENER, Jeffrey JOHNSON, David B. KAY.
Application Number | 20220249142 17/726709 |
Document ID | / |
Family ID | 1000006289060 |
Filed Date | 2022-08-11 |
United States Patent
Application |
20220249142 |
Kind Code |
A1 |
JOHNSON; Jeffrey ; et
al. |
August 11, 2022 |
OSTEOTOMY PLATE, PLATE DRIVER AND METHOD FOR THEIR USE
Abstract
An orthopedic plate is specifically configured for use in
osteotomies, in which part of the plate extends into a portion of a
first bone segment and part is external to the cortical surface of
an adjacent bone segment to fix the segments to allow them to fuse.
The plate has a first end and a second end where the end which is
inserted into the bone has a chamfer and a through hole having a
hole axis optionally at an oblique angle to the longitudinal axis
of the plate, and which can receive a screw, peg or pin. The second
end of the plate includes a locking screw hole and optionally
including a compression slot extending in a direction toward a
screw hole in the opposing end. Optionally, the non-locking hole
has a shroud that forms an arc or portion of a cylinder over the
hole. A plate driver having a recess that holds the plate is used
to insert the plate into the bone.
Inventors: |
JOHNSON; Jeffrey;
(Chesterfield, MO) ; KAY; David B.; (Akron,
OH) ; HEAVENER; Jackson R.; (Warsaw, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
OrthoHelix Surgical Designs, Inc. |
Medina |
OH |
US |
|
|
Assignee: |
OrthoHelix Surgical Designs,
Inc.
Medina
OH
|
Family ID: |
1000006289060 |
Appl. No.: |
17/726709 |
Filed: |
April 22, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16454119 |
Jun 27, 2019 |
11337737 |
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17726709 |
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15880952 |
Jan 26, 2018 |
10368926 |
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16454119 |
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15413968 |
Jan 24, 2017 |
9888949 |
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15880952 |
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14625657 |
Feb 19, 2015 |
9572607 |
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15413968 |
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12803852 |
Jul 8, 2010 |
8986353 |
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14625657 |
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61270486 |
Jul 9, 2009 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 17/1728 20130101;
A61B 17/809 20130101; A61B 17/8605 20130101; A61B 17/92 20130101;
A61B 17/8061 20130101; A61B 17/808 20130101; A61B 17/8052 20130101;
A61B 17/8014 20130101; A61B 17/1775 20161101; A61B 17/8057
20130101; A61B 17/1782 20161101 |
International
Class: |
A61B 17/80 20060101
A61B017/80; A61B 17/17 20060101 A61B017/17; A61B 17/92 20060101
A61B017/92; A61B 17/86 20060101 A61B017/86 |
Claims
1-16. (canceled)
17. A plate for bone fixation comprising: a first end; a second end
with a deep chamfer which tapers from a lateral edge of the plate;
a bottom surface configured for contact with a bone; a top surface
spaced-apart from the bottom surface, wherein an open-ended
passageway communicates between the top surface and the bottom
surface, the open-ended passageway being defined in offset relation
to at least one of the top surface and the bottom surface, with a
portion of the top surface circumferentially adjacent a top
open-end of the passageway that is configured to receive a head of
a screw within an angle of rotation of up to 20.degree.; and a
shroud extending outward from the top surface at an oblique angle
and covering at least a portion of the top open-end, the shroud
adapted to be interposed between a tissue and the head of the screw
so as to prevent tissue irritation and provide compression to the
bone.
18. The plate of claim 17, wherein the plate has a distal edge
having a larger thickness to provide a broader shoulder so as to
allow for the proximal portion of the plate to be driven into a
bone.
19. The plate of claim 17, further comprising a compression slot
passageway communicating between the top surface to the bottom
surface.
20. The plate of claim 17, wherein an axis of the passageway forms
an angle of between 10.degree. and 45.degree. with the top
surface.
21. The plate of claim 17, wherein an axis of the passageway forms
an angle of between 15.degree. and 40.degree. with the top
surface.
22. The plate of claim 17, wherein an axis of the passageway forms
an angle of between 25.degree. and 35.degree. with the top
surface.
23. The plate of claim 17, wherein a cutting edge is formed at the
first end.
24. A plate for bone fixation comprising: a bottom surface
configured for contact with a bone; a top surface arranged in
spaced-relation to the bottom surface, wherein an open-ended
passageway is defined between the top surface and the bottom
surface sized to permit a screw to be inserted therethrough with a
less than 90.degree. angle between a screw axis and a passageway
axis to allow for a conical rotation of the screw, the passageway
configured to receive a head of the screw wherein the passageway
axis forms an angle with respect to the bottom surface between
10.degree. and 45.degree.; and an arcuate shroud projecting
outwardly from the top surface at an oblique angle and covering at
least a portion of an open-end of the passageway, the shroud
adapted to be interposed between a tissue and the head of the
screw.
25. The plate of claim 24, wherein the angle of the passageway axis
with respect to the bottom surface is between 15.degree. and
40.degree..
26. The plate of claim 24, the angle of the passageway axis with
respect to the bottom surface is between 25.degree. and
35.degree..
27. The plate of claim 24, further comprising a second open-ended
passageway is defined through the plate that communicates between
the top surface and the bottom surface.
28. The plate of claim 24, further comprising a tapered
crescent-shaped cutting edge.
29. A plate system for use in associated bone comprising: a
non-locking screw having distal threads and a head having a rounded
surface without external threads; and a plate having: a first end
and a second end with a longitudinal axis defined between the first
end and the second end; a bottom surface configured for contact
with a bone; a top surface spaced-apart from the bottom surface,
wherein an open-ended passageway communicates between the top
surface and the bottom surface, the open-ended passageway being
defined in offset relation to at least one of the top surface and
the bottom surface, with a portion of the top surface
circumferentially adjacent a top open-end that is configured to
receive the head of non-locking screw within an angle of rotation
of up to 20.degree.; and a shroud projecting outwardly from the top
surface at an oblique angle and covering at least a portion of the
top open-end, the shroud adapted to minimize interaction between a
tissue and the head of a non-locking screw.
30. The plate of claim 29, wherein the plate has a distal edge
having a larger thickness to provide a broader shoulder so as to
allow for the proximal portion of the plate to be driven into a
bone.
31. The plate of claim 29, wherein the passageway is shaped so as
to permit the screw to be inserted therethrough with an angle
between a screw axis and a passageway axis of up to 20.degree. of
conical rotation.
32. The plate of claim 29, wherein an axis of the passageway forms
an angle of between 10.degree. and 45.degree. with the top
surface.
33. The plate of claim 29, wherein an axis of the passageway forms
an angle of between 25.degree. and 35.degree. with the top
surface.
34. The plate of claim 29, wherein a straight taper cutting edge is
formed at the first end.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to an orthopedic plate, which
is configured for the fixation of a bone or bones of the foot, hand
or wrist in particular following a procedure for fusion of adjacent
segments or reconstruction such as various osteotomy procedures.
The invention also relates to a surgical driver that is used to
implant the osteotomy plate and to a method for the use of the
orthopedic plate and associated driver in surgical
reconstruction.
BACKGROUND OF THE INVENTION
[0002] The feet and the hands both include numerous bones and
joints that cooperate together to define quintessential human
movement. They are sophisticated, delicate and altogether elegant
in function and design. Together the foot and ankle have over 25
bones and 33 joints along with more than 100 named muscles,
tendons, and ligaments and a network of blood vessels, nerves, all
residing beneath a relatively slim covering of soft tissue and
skin. Structurally, the foot has three main anatomical regions: the
forefoot, the midfoot, and the hindfoot. These parts work together
with the ankle, to provide the body with support, balance, and
mobility. A structural flaw or malfunction in any one part can
result in the development of problems, which are manifested in
other areas of the body. The hand forms a cognate to the foot with
27 bones within the hand and wrist. There are eight small bones
within the wrist called the carpals, which join with the radius and
the ulna to form the wrist joint. The carpals connect with the five
metacarpals to form the palm of the hand, which terminate in the
rays (i.e., the thumb and fingers) formed by the phalanges. The
three phalanges in each finger are separated by two joints, called
interphalangeal joints (IP joints). The one closest to the MCP
joint (knuckle) is called the proximal IP joint (PIP joint). The
joint near the end of the finger is called the distal IP joint (DIP
joint). The thumb only has one IP joint between the two thumb
phalanges. The IP joints of the digits also work like hinges when
you bend and straighten your fingers and thumb.
[0003] Similarly, the forefoot includes the five toes (which are
also known as the "phalanges") and their connecting long bones (or
"metatarsals"). Several small bones together comprise a phalanx or
toe. Four of the five toes have three phalanx bones respectively
connected by two joints. The big toe (or "hallux") has two phalanx
bones distal and proximal with a joint in between called the
interphalangeal joint. The big toe articulates with the head of the
first metatarsal at the first metatarsophalangeal joint (the "MTP"
joint) and there are two tiny, round bones called sesamoids on the
plantar side of the metatarsal head. The phalanges are connected to
the metatarsals at the ball of the foot. The forefoot balances
pressure on the ball of the foot and bears a substantial amount of
the body weight.
[0004] The bones of the midfoot from medial to lateral are the
1.sup.st through 3.sup.rd cuneiform, the cuboid, and the crescent
shaped navicular bone posterior to the cuneiforms, which also forms
a joint with the talus that forms the basis for the ankle joint at
the hinged intersection of the tibia, the fibula, and the foot. The
five tarsal bones of the midfoot act together form a lateral arch
and a longitudinal arch which help to absorb shock. The plantar
fascia (arch ligament) underlays the bones of the midfoot and along
with muscles, forms a connection between the forefoot and the
hindfoot. The toes and their associated midfoot bones form the
first through fifth rays beginning with the great toe as the first
ray. The bones which form the palmate portion of the hand are: the
scaphoid, the lunate, the triquetrum, the pisiform, the trapezium,
the trapezoid, the capitate, and the hamate, which act in concert
to allow the opposition of the thumb with each of the fingers and
to permit the uniquely human ability to manipulate objects.
[0005] The hindfoot is composed of three joints (subtalar,
calcaneocuboid & talonavicular) and links the midfoot to the
ankle. The heel bone (or "calcaneus") projects posteriorly to the
talus and forms a lever arm to activate the hinged action of the
foot so as to allow propulsion of the entire body from this joint.
The calcaneus is joined to the talus at the subtalar joint. The
mid-foot is often the subject of trauma, such as results from
falls, vehicle crashes and dropped objects. These accidents often
result in severe fractures and/or dislocations. In addition, there
are several conditions which result from congenital deformation or
which arise as a result of repeated use type injuries. Surgical
intervention that includes surgical sectioning of bone or an
"osteotomy" is often used to restructure the bones as a treatment
for such conditions. For example, the calcaneal translational
osteotomy, with which the present invention might be used, is
typically used to treat a condition that is the result of adult
acquired flatfoot deformity. The present invention is likewise
useful for conditions of the hand that result from prior trauma,
surgical intervention or defects from birth or that develop with
age (such as rheumatoid arthritis).
[0006] Examples of some of the other procedures with which the
present invention could be used include hallus valgus and hallus
rigidus corrections, and bunionectomies. Other applications which
could use the present invention include first and fifth metatarsal
chevrons, translational osteotomies, closing wedge osteotomies,
pediatric femoral osteotomies, metacarpal and calcaneal rotational
osteotomies, intrarticular osteotomies and hand and wrist
realignment osteotomies.
[0007] Typical surgical treatment of the foot or hand
re-establishes a normal anatomy while the fractured bones mend. In
some cases, fusion of a joint may be necessary, for example, where
arthritis arises in a patient due to use injuries, poor bone or
prior unsuccessful surgeries. One current surgical treatment of
these conditions requires that pins, wires and/or screws be
inserted to stabilize the bones and joints and hold them in place
until healing is complete. For example, a pin or screw may be
introduced medially into the internal cuneiform and through the
base of the second metatarsal bone. While the use of k-wires, pins,
and screws may provide acceptable results for younger and more
plastic patients, these methods of fixation are not always
satisfactory.
SUMMARY OF THE INVENTION
[0008] In accordance with the present invention an orthopedic plate
(as well as a driver for the plate) is provided which can be used
to good advantage in an osteotomy. In a first embodiment, the plate
has a footprint that is a modified rectangle having a first end
with rounded corners, and a longitudinally opposing end with a
cutting edge that may include a taper or a crescent shape. Either
two or three of the four sides of the plate, including both long
sides and optionally the proximal end have a raised edge or rails
which acts to stabilize the plate, and which is connected with a
thinner flat web of material that includes one or more holes for
screws or pins. At the cutting end, the rails may terminate in
pointed insertion tips which are joined by the web that also
includes a tapered cutting surface or the plate may simply include
the tapered cutting edge. In a second embodiment, the plate has a
simple bar-like footprint with a first end tab and a second end tab
extending along the longitudinal axis of the plate and with
narrowed waist sections between the tabs. At the first end tab, the
plate includes a first portion that is inserted into cancellous
bone. This portion includes a rounded or tapered chamfered edge
that promotes insertion into the bone. At the second end tab, the
opposing portion includes a through hole so that the plate can be
fixed to an extramedullary portion of an adjacent bone segment.
Optionally, the plate includes a compression or translation slot
that extends in a direction and causes compression toward a through
hole in the opposing cancellous tab. The width of the plate
decreases between the holes to allow for bending if desired. In
other embodiments, the footprint may by more "organic" in shape,
with a rounded tapered insertion surface, a mid-section that flares
to accommodate an angled screw hole and a rounded rear section that
includes a second perpendicular screw hole. In a further
modification of this plate, the plate advantageously includes an
angled hole with a shroud that protects the soft tissue from the
head of the screw and which aids in optimal compression of the
posterior fragment for certain procedures.
[0009] The invention can be used in a variety of indications
including for example, calcaneal osteotomies Dwyer osteotomy,
cotton osteotomy, isolated TMT fusion, Navicular fracture, Evans
osteotomy and metacarpal rotational osteotomies, or intrarticular
osteotomies or hand and wrist realignment osteotomies. Other
applications which could use the present invention include first
and fifth metatarsal chevrons, translational osteotomies, and
closing wedge osteotomies.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1a is a medial view of a foot with an orthopedic plate
in accordance with a first embodiment of the invention positioned
for use in a translational calcaneal osteotomy procedure;
[0011] FIG. 1b is a medial posterior view of a foot with a further
embodiment of the plate of the present invention also for use in a
translational calcaneal osteotomy procedure;
[0012] FIG. 2 is a top view of the orthopedic plate of FIG. 1;
[0013] FIG. 3 is a side view of the plate shown in FIG. 2;
[0014] FIG. 4 is an end view of the plate shown in FIG. 3;
[0015] FIG. 5 is a top perspective of the plate shown in FIG.
2;
[0016] FIG. 6 is an end perspective of the plate shown in FIG.
2;
[0017] FIG. 7 is a bottom perspective of the plate shown in FIG.
2;
[0018] FIG. 8 is a side perspective of the plate shown in FIG.
2;
[0019] FIG. 9 is a top view of a second embodiment of the
orthopedic plate of the present invention;
[0020] FIG. 10 is a side view of the plate shown in FIG. 9;
[0021] FIG. 11 is an end view of the plate shown in FIG. 10;
[0022] FIG. 12 is a top perspective of the plate shown in FIG.
9;
[0023] FIG. 13 is an end perspective of the plate shown in FIG.
9;
[0024] FIG. 14 is a bottom perspective of the plate shown in FIG.
9;
[0025] FIG. 15 is a side perspective of the plate shown in FIG.
9;
[0026] FIG. 16 is a top view of a third embodiment of the
orthopedic plate of the present invention;
[0027] FIG. 17 is a side view of the plate shown in FIG. 16;
[0028] FIG. 18 is an end view of the plate shown in FIG. 17;
[0029] FIG. 19 is a top perspective of the plate shown in FIG.
16;
[0030] FIG. 20 is an end perspective of the plate shown in FIG.
16;
[0031] FIG. 21 is a bottom perspective of the plate shown in FIG.
16;
[0032] FIG. 22 is a side perspective of the plate shown in FIG.
16;
[0033] FIG. 23 is a side perspective of the fourth embodiment of
the orthopedic plate of the present invention;
[0034] FIG. 24 is a side perspective of the fifth embodiment of the
orthopedic plate of the present invention;
[0035] FIG. 25 is a side perspective of the plate driver of the
present invention;
[0036] FIG. 26 is a top view of the plate driver shown in FIG.
25;
[0037] FIG. 27 is a side view of the plate driver shown in FIG.
25;
[0038] FIG. 28 is a bottom view of the plate driver shown in FIG.
26;
[0039] FIG. 29 is a first end view of the plate driver shown in
FIG. 25;
[0040] FIG. 30 is a second end view of the plate driver shown in
FIG. 25;
[0041] FIG. 31 is a bottom perspective of the plate loosely
attached to the plate driver in accordance with the invention;
[0042] FIG. 32 is a side view of the plate and driver in accordance
with the invention during insertion;
[0043] FIG. 33 is a side view of the plate and driver in accordance
with the invention during insertion;
[0044] FIG. 34 is a side view of a non-locking screw in accordance
with the invention;
[0045] FIG. 35 is a side view of a locking screw in accordance with
the invention; and
[0046] FIG. 36 is a side view of a variable locking screw in
accordance with the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0047] FIG. 1 shows a skeletal version of a foot from the lateral
side with a particularly preferred embodiment of the plate 210 of
the present invention in place between the junction of the talus
and the calcaneus with an angled screw inserted into the
Sustentaculum Tali. Thus, FIG. 1 illustrates the plate used in a
translational osteotomy of the calcaneus for treatment of flatfoot
syndrome. Similarly, it can be used for fixation of other bone
segments following osteotomies as previously mentioned.
[0048] As viewed from the top in FIG. 2, it can be seen that the
first embodiment of the plate 10 has a rectangular shape with a
first end 12 and an opposing cutting end 14 aligned along the
longitudinal axis of the plate. The peripheral edges 16 of the
plate are raised on three sides, including the two long sides 18,
19 and the squared short wall 20. These edges form rails that help
to provide stability for the plate and in particular to inhibit
torsion of the plate during insertion and during the recuperation
period in which the injury fuses. The rails are rounded at the
corners of the squared short wall 20. The opposing short wall
includes a chamfered cutting surface 22, which is illustrated as a
crescent shape between the two forward extending insertion tips 24
that are coextensive with the long wall edges. The body of the
plate is formed by a thinner flat web 25 that extends between the
raised edges and includes a number of openings.
[0049] Preferably, the web 25 includes a first opening 26, or hole
in the portion of the plate which extends into the bone and which
accepts a screw or a pin in order to help hold the plate in place
and to keep it from rotating within the bone. Rearward of that, and
somewhere beyond halfway along the long axis of the plate, the
plate includes a compression slot 27 that accepts a screw to cause
compression toward the first opening. Typically, the compression
slot includes a shoulder 28 along its internal edge 29 that slopes
in the direction that compression occurs. In the rearward portion,
toward the squared end, the plate includes a locking hole 30 which
includes a mechanism to cause locking, such as internal threads
that mate with external threads on the head of a locking screw to
lock this portion of the plate to the extramedullulary portion of
an adjacent bone fragment.
[0050] In a second embodiment, the plate 110 has a simple bar-like
profile that is comprised of a first end with a tab and a second
end with a longer tab. The longer tab 112 has a rounded end at its
proximal end that necks in slightly into the body of the first tab
112, and the rounded end includes a deep chamfer 115 which tapers
from the lateral edge of the plate to an optional through hole 116
which can receive a screw or pin that helps to secure the plate in
the cancellous portion of the bone against rotation or movement.
The longer tab also includes an obround translation or compression
slot 120 at the distal end of the first tab. The plate width flairs
slightly around the slot to preserve the metal which defines the
slot (preferably to reinforce the slot to inhibit deformation of
the slot during any option bending procedures, or even during
insertion. Again the plate necks in slightly at the transition
between the first tab and the second tab and the distal most 114 of
the pair of tabs includes a screw hole 122 (which preferably
includes locking means such as internal threads or a variable
locking mechanism, so as to form a locking interface between the
plate and the respective bone or bone fragment by means of the
rigid fastening of the screw in the screw hole in the plate.) The
locking hole optionally further includes keyways for a drill guide.
The compression slot is configured so as to cause compression along
the longitudinal axis of the plate in the direction of the locking
screw hole. The plate includes incurvatures 123 between the
openings to form waist sections that minimize the material used and
maximizes the fit of the plate, as well as allowing additional
contouring of the plate in these areas, should it be desired.
[0051] In a third embodiment, the plate 210 corresponds in shape
and function to the second embodiment. Specifically it has a first
rounded tab end having a deep chamfer that permits the plate to be
inserted into bone and a second rounded end having a threaded
locking screw hole. In this embodiment, the compression slot is
replaced by an angled non-locking screw hole 220 which includes a
hole shroud 222 forming an arc or a portion of a cylinder raised
above the top surface of the body of the plate in order to
sufficiently support the screw that is received in this hole and to
shroud the head of the screw to help minimize the possibility of
soft tissue irritation that the screw head might otherwise provide.
The shroud also provides some support and compression within the
bone into which it projects. The non-locking hole is angled so that
the axis of the screw forms an angle of about 10.degree. to about
45.degree., and preferably about 15.degree. to about 40.degree.,
and more preferably about 25.degree. to about 35.degree. to the
longitudinal axis and the hole allows for about 30.degree.,
preferably about 20.degree., and most preferably about 15.degree.
of conical rotation of the screw within the screw hole of the plate
which is provided to enable the surgeon to capture the
sustentaculum. This screw is intended to capture the anterior
portion of the calcaneus in a calcaneal osteotomy.
[0052] FIGS. 3 and 4 illustrate the edge on views of the first
embodiment of the plate in along a first length and along the
second shorter length, which is perpendicular to the first length.
As can be seen the web of the plate has a generally uniform
thickness between the inward surface 27 which opposes and
optimally, but not necessarily engages the bones, and the outward
surface 29. Similarly, the second embodiment is illustrated in edge
on views in FIGS. 10 and 11 in which it can be seen that this
embodiment that the plate is flat and of a uniform thickness
between the bone-facing surface of the cortical portion of the
plate. Optionally, the inward surface 127 of the plate 110 could
includes a generally uniform radius of curvature along the
longitudinal axis so that the plate would have the shape of a
segment of a cylinder which maximizes the ability to place the
plate as desired without the need for additional pre-surgical
contouring for certain applications, although the plate thickness
allows for bending if necessary Also optionally for this design,
the distal edge of the plate can be of a larger radius or thicker
width to provide a broader shoulder 136 so that the proximal
portion of the plate can be driven into the bone.
[0053] FIGS. 23 and 24 illustrate other embodiments 310, 410 of the
orthopedic plate of the present invention that illustrate how
different features of the previous embodiments could be combined,
including the straight taper cutting edge, and with the compression
slot or with the angled screw hole and shroud.
[0054] FIGS. 25 through 30 illustrate the plate driver 500 of the
present invention. The driver 500 includes a plate holder portion
510, which has at one end a recess or pocket 515 that captures the
end of the plate 600 (see FIG. 31) having the locking hole.
Specifically, the plate holder 510 includes a knob 517 joined to a
shaft 518 that is journaled within a bore 519 in the plate holder
510. The end of the shaft 518 includes threads that can engage the
internal threads of the locking hole in the plate to hole the plate
within the plate holder as well as relative to the plate driver.
The plate driver further includes a handle 520 that allows the
surgeon to hold the plate driver. The plate holder portion holds
the plate with the long axis in line with the long axis of the
handle, but offset from the plate which gives the surgeon better
visibility to the surgical site. Further, the handle 520, includes
fenestrations 522 which lighten the weight of the plate driver, and
at the end of the handle, there is a buttressed area 525, which has
a wider flat surface that can be used to tap the plate into the
bone. FIGS. 32 and 33 illustrate a plate 600 being inserted into
the cortical section of a calcaneus using the plate driver 500.
[0055] The screws useful with the plate of the present invention
are self-starting, self-tapping screws including the option of
partial or full cannulation. The screws include a cutting 142 end
having multiple flutes 144, and preferably 2 or 3 flutes about a
conical recess. The screws further include a partial taper 132 of
the inner diameter in the proximal end over the first several
thread turns, for example over 2-8, and preferably over 3-5 turns
in order to increase the fatigue life of the screw as well as
providing potential physiological advantages in use. The screws
further include a torque driving recess. The screws 120, 140, 150
have a threaded distal end and a head including a torque driving
recess 156. The head of the locking screw includes locking means,
such as a variable locking mechanism 160, which could be a bushing
that mates with the screw head so as to lock the screw relative to
the plate at a desired angle, or could include external screw
threads 134 that mate with internal threads in the locking screw
hole at a pre-selected angle, in this instance, the screw axis is
perpendicular to the longitudinal axis of the plate. The screw used
in the compression slot has a rounded rear shoulder (such as a
hemisphere, or a torroid) which mates with the concavely rounded
groove of the compression slot so as to maximize surface contact
between the screw head and the inclined geometry of the compression
slot. The lateral edge of the compression slot further includes an
inclined shoulder that slopes downward toward the bone-contacting
surface of the plate and which is engaged by the screw head to
cause the translation of the screw and attached bone fragment along
the long axis of the slot and towards the locking hole.
[0056] The plate is formed of a biocompatible material, and
preferably a metal such as surgical grade stainless steel, titanium
or a titanium alloy or a cobalt chromium alloy. Preferably, the
plate web has a thickness of between about 1.0 and about 2.5
millimeters, more preferably between about 1.5 and about 2
millimeters, and most preferably between about 1.5 and about 1.8
millimeters. The plate includes a raised continuous outer edge 16
which is defined between the top and the bottom surface and which
has a total thickness of about 2 and 5 millimeters, or roughly
twice the width of the web portion of the plate.
[0057] In addition, the plate can include a small through hole
sized to receive a K-wire or other similar guide wire.
[0058] During the surgery the joints are first prepped which may
include de-articulation between the bones to be fused and removal
of any bone as part of the osteotomy, and as necessary, the plate
is bent to contour to the bone surface. A pilot hole may be drilled
into the bone into which the plate will be inserted. The plate is
inserted into the plate recess in the plate driver and secured by
tightening the plate upward in the plate holder using the plate
holder having an end that has threads which mate with the locking
threads of the locking hole in the plate. The plate is tamped into
the cancellous portion of the bone fragment optionally by tapping
the plate driver with a one pound mallet as is necessary to insert
the plate. The plate should be driven until the recess or pocket
makes contact with the anterior portion of the calcaneus. Once the
plate is sunk, a drill guide is mated to the plate drive, and a
hole is drilled for the locking screw. The plate can be held in
position using olive wires (thru the non-locking hole and into the
bone). The plate is located such that all of the screws are aimed
into the targeted bones and away from the joint, fracture, or bone
interface. The olive wire is removed if used, and a pilot hole is
drilled at the end of the plate that includes the first hole and
this hole is pinned or screwed. A second pilot hole may be drilled
for the non-locking screw at the desired angle given an optional
15.degree. of conical rotation within the non-locking hole and a
non-locking screw is inserted into this pilot hole and tightened.
As the screw is tightened in the angled hole, it will drive
compression toward the fusion site and the first hole. The plate
allows for up to 1.5 millimeters of compression. Finally, a pilot
hole is drilled in the cortical surface of the second bone
fragment, for example using a drill guide such as a guide including
keyway guides (i.e. lobes) that interlock with corresponding keyway
openings in the locking screw hole and a locking screw is secured
in this hole. The plate is viewed radiographically, and the soft
tissues are closed in the usual manner.
[0059] This invention has been described in detail with reference
to specific embodiments thereof, including the respective best
modes for carrying out each embodiment. It shall be understood that
these illustrations are by way of example and not by way of
limitation.
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